Currently, optical networks having complex topological structures such as interconnected ring networks and mesh networks are constructed by use of OADMs (optical add drop multiplexer), WXCs (wavelength cross-connects), and the like. The OADMs insert (add) and remove (drop) optical signals into (to) and from a multiplexed optical signal on a wavelength-by-wavelength basis, and the WXCs switch paths of optical signals on a wavelength-by-wavelength basis.
In the above situation, demands for a tool for performing efficient design of an optical network including optimum design of arrangement of various devices such as dispersion compensators are increasing.
According to some conventionally proposed techniques, the amounts of dispersion compensation by dispersion compensators arranged in respective paths are set so that the residual dispersion in each path is within a tolerance of the residual dispersion. For example, see Japanese Republication of International Patent Publication WO2005/006604, page 6, line 46 to page 8, line 26, and Japanese Laid-open Patent Publication No. 8-297591, paragraph Nos. 0009 to 0012 and FIG. 1.)
However, according to the mainstream techniques used in the conventional tools for designing an optical network, an optical network is designed in consideration of only one design item as a target as in the above-mentioned conventionally proposed techniques (in which the residual dispersion is controlled within a predetermined range). Therefore, conventionally, it is impossible to efficiently design an optical network having one or more desired characteristics by concurrently considering a plurality of design items.